With a development of economy and technology, a display, especially a liquid crystal flat display apparatus, is more popular in an application of a computer, a mobile device, a multimedia and a TV display, etc. In order to reduce a picture flicker and crosstalk caused by direct current afterimage during a driving display process of the liquid crystal and fluctuations in a common voltage arising from a coupling to a common electrode from signal lines, the current driving manners in most of the liquid crystal panels utilize a dot reversal, 2-dot reversal, and a (1+2)-dot reversal as the polarity reversal method. At a time of displaying some special evaluation patterns, the common voltage would not return to a normal value when the next frame starts if a coupling effect to the common electrode by the data signals is large, such that the flicker in the picture or the crosstalk in several initial rows of the picture is serious; also, during a scan process for the same frame, the crosstalk phenomenon in the picture of entire screen is very serious, if the coupling effect to the common electrode by the data signals is large and a polarity reversal frequency among rows is relatively high.
In FIG. 1, a) and b) are two display patterns under a driving method of an existing 1+2 dot reversal. In view of a TN normal-white mode, assuming a voltage difference between a sub-pixel electrode and the common electrode in non-shadow region as 0V and that in shadow region as 1V. For a) in FIG. 1, the voltage Vcom of the common electrode in the current frame is pulled-up, but the Vcom could not return to the normal value at the time of the next frame reversing polarity, which causes an actual voltage difference between the liquid crystal pixel electrode in the next frame and the voltage Vcom being increased, such that a transmittance of LC (liquid crystal) is below a predetermined value and a flicker occurs in two neighbor frames. For b) in FIG. 1, the date signals in part of the rows pull up the voltage Vcom while the data signals in another part of the rows pull down the voltage Vcom in a same frame, therefore such process for pulling the Vcom from up to down or from down to up would influence an effective voltage input of the pixels in the next row. As illustrated in b) of FIG. 1, the Vcom is pulled-up at the first row, therefore the voltage difference between the pixel voltage of sub-pixel G and the Vcom is smaller than a predetermined value, while the voltage differences between the pixel voltage of sub-pixels R, B and the Vcom are larger than a predetermined value, respectively, when the pixel signals of the second row is written, which would cause the sub-pixel G is brighter but the sub-pixels R and B are darker, such that a green crosstalk or color offset may be generated. The frequency of pulling the Vcom up/down from respective rows in the same frame is higher, the phenomenon of green crosstalk or color offset is severer.
In FIG. 2, A, B, C and D illustrate several common-used display patterns for evaluating the flicker and crosstalk currently. In the existing polarity reversal driving method, there is always one of the patterns which would deteriorate the phenomenon of flicker or crosstalk obviously.